Attenuation devices for smoothing of pressure surges in fluid systems and for reducing the resulting vibrations and noise can be divided mainly into two known groups of attenuation devices. One group includes hydropneumatic attenuators such as hydraulic accumulators containing an additional gas volume, for example. The other group includes fluid sound attenuators, so-called silencers, in which without an additional gas volume an attenuation effect takes place by reflection or absorption.
The hydropneumatic attenuators typically attenuate a frequency band extending from very low frequencies to about 400 Hz. As such, the hydropneumatic attenuators are particularly suitable for use in fluid systems in which pressure pulsations occur in this frequency band due to operation of compressors, engagement and disengagement processes of the compressors, as well as operating processes of the compressors. Since the hydropneumatic attenuators with additional gas volumes are both bulky and heavy, the hydropneumatic attenuation devices cannot be used in many applications where installation space is limited and a lightweight construction is necessary, as is the case, for example, in air-conditioning systems in motor vehicles. Other disadvantages of attenuation devices with an additional gas volume are that the attenuation action varies depending on a temperature and that the attenuation action overall is degraded by gas losses due to permeation.
Conversely, the fluid sound attenuators are far more compact and have a lightweight construction. However, use of the fluid sound attenuators is limited by the attenuation action being sufficient only at higher frequencies. Because of this limitation, the fluid sound attenuators are typically not ideal for use in air-conditioning circuits, which produce a very wide frequency band extending from very low frequencies to very high frequencies.
It would be desirable to produce an attenuation device which is configured to attenuate acoustic energy over a wide range of frequencies, wherein a structural complexity and a package size thereof are minimized.